Finished my build of a '31 Model A, with a '53 flattie. It's the usual, .040 over, Offy heads, Isky cam, solid lifters. But now to the problem. I have a complete set of NEW Dolphin gauges. However, when I hooked up the Temp gauge, it reads about 210 to 215 degrees. But the engine isn't that hot. Using a temp gun, I can't find any where on the heads, block radiator hoses, radiator, etc, any reading higher than 168 to 170 degrees. I even went to the extent of using a temp probe that is used for my deep fryer, and reads 150 to 160 degrees. I've been on the phone with Dolphin's tech guy several times, and I have replaced both of the temp senders units, and now the gauge. I've found that if I disconnect one or the other of the senders (makes no difference which one), it reads 165 degrees. I'm using 160 degree thermostats. Hower, if both are hooked up at the same time, it reads the high temps. One thing I did do wrong, and have corrected, is that I was using a common ground for all the gauges. I now have a designated ground wire for each gauge. The Dolphin tech guy has been helpful and courteous, but I'm still in the same boat. Any suggestions would be much appreciated.
How are the gauges wired? And the temp sensors? Do you have the grounds run together? Grounded to the same point? Could have a “ground loop” Are you wiring to the senders together ? Try running them sepperate ( isolate any unwanted noise) Have not heard good things about dolphin products. Do you have another gauge /sender combo to try? Even a cheapo HF unit would be fine to confirm findings
Are you trying to run one gauge off of two sender's? If so, you answered your own question when you disconnected one of the sender's. Not sure how you can make their gauge work with two sender's connected.
Has Dolphin said you can hook both senders together to operate one temp gauge like the original ford senders were? I'm assuming from your post that is what you have done. I did a 52 Ford flathead last year, 1 gauge and 2 senders. Each sending unit wired to a switch so the gauge could read one sender at a time. Better would be to have a gauge for each sender, but I didn't have that option available to me. I've never seen an aftermarket gauge that would accurately read 2 sending units at the same time. That doesn't mean one doesn't exist, but my search last year didn't come up with anything I thought would work.
I've been through that years ago. The only gauge I've found that will read correctly with 2 senders is the factory Ford unit. That's why I'm running all stock 36 gauges in my V-8 Roadster. Your options are to mount a second dolphin gauge or use a rocker type switch that will remove one sender and connect the other pending position to read with one gauge. By the way, I have installed a few sets of Dolphin gauges in customers cars and not had any issues with them. As far as I know the Customers are still running them. The Wizzard
>> "The Dolphin tech guy has been helpful and courteous, but..." does not understand wiring 2 resistors in parallel. The temperature senders are resistors that change resistance as they heat up. In this case, the resistance (that property that "resists" current flow) decreases with increased temperature. The temperature gauge is "reading" the current flow through the temperature sender. Two (2) equal resistors wired in parallel will reduce the measured resistance by one half (and double the current flow). As posted above, your options are; 1. Only connect to one temperature sender and ignore the other one/ 2. Two (2) matched temperature gauges, different brands may NOT be compatible with the Dolphin temperature sender. 3. Install a Single Pole - Double Throw (SPDT) toggle switch. "Your temperature readings may vary..."
One gauge, one sender. That is why I have two temp gauges in my dash, one left, each one right going to separate sending units in the flat head. You can run one gauge with the sending units run through a toggle switch or so I hear. I decided my temp was worth more than the amps in my 5 gauge panel. BYW, I have a SW wings amp gauge for sale.
Thanks to all who have responded. As I mentioned in my original post, I got another gauge from Dolphin, to replace the original. Tech guy thought the original may have been a bad gauge. What I have done to correct all the problems is actually pretty simple. I have a finned aluminum 5 gauge dash cluster. Speedo, oil pressure, volts, water temp and gas gauge. My fuel tank, mounted in the trunk, doesn't have an electric sender. It has the built in float gauge you read on top of the tank. Anyway, I took the original temp gauge, and swapped it out with the non functional gas gauge. So now I have a WORKING PAIR of water temp gauges, side by side. One for the left sender, and one for the right sender. All in now well with the world. I have heard a lot of what guys think about Dolphin. And although they were very friendly and helpful, they did know I was doing a flattie, and he said they had never had this problem before.?!. And we went through the whole range of "did you do this and did you do that", I was still getting nowhere. In fact he sent me the 2nd gauge free, when he thought the original was bad. So I took the hint from all you guys who said to run two gauges. Again, many thanks to all who responded and suggested differing solutions. Much appreciated. Shake-n-Bake
@shake-n-bake May your flathead shake and doesn't bake. Thanks for posting the fix, you never know who it will help next.
Curious, because I have Faria gauges in my '31. Well established in the marine field, but,apparently, they made auto gauges for a few years in the early 90's. Beautiful gauges,well made and when I needed a replacement bulb, they sent me an entire baggie full.
I have used dolphin gauges a few times and never had a problem, of course I spent the last 30 yrs of my working carrier as an instrument Technician. And of course I like to fish,LOL.
Test the gauge.sender in boiling water. The temp on the outside of the motor, is not the same as the temp on the inside.
Glad you got it figured out and fixed. I bought So. Cal gauges and while I don't care for the red and white "football" logo on the gauge faces, I love the convex lenses on them. I had a volt meter that didn't work, right outta the box and ordered a new one from them [had the gauges for over a year before installing them] and when I paid for it I mentioned on the order form that the first one didn't work. They sent me the new one a few weeks ago and I just noticed today my paypal acct was credited the cost of the new gauge...Thanks, So Cal!
This is one of those where are picture is worth more than all the wording in the world. I don't even think Dolphin tech was aware that one water temp gauge was being fed resistance reading(s) via two sending unit's.
When ford used 1 gauge with 2 sending units. The 2 wire sending unit was a thermal switch (that would go open at a given temp). the single wire one was a normal sending unit (changes resistance with temp), The gauge read the resistance through the thermal switch in one cylinder head to the real sending unit in the other. if the thermal switch got hot enough to open up the gauge went to full hot. The two gauges you have right now will let you accurately know what is going on in both side of the engine.
So it sounds like you could use the thermal switch and a new sender that matches the new gauge and it should work just like the factory Ford setup did. Provided that the new gauge goes to hot when power is disconnected.
It's very doubtful that a sender of proper value like that of an aftermarket (any of them) could even be found that will do double duty.
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